Square D QMB365W – 400A, 600V, 3-Pole Fusible Panelboard Switch – QMB Series

The Square D QMB365W is a rugged 400A, 600V, 3-pole fusible panelboard switch designed to deliver dependable load disconnect and precise overcurrent protection within QMB fusible panelboards. Built for demanding electrical distributions, it provides clean isolation for maintenance and reliable protection for connected circuits, so your system stays safer and more reliable during service or fault events.

• Balanced 3-pole design ensures consistent isolation across all phases in a three-phase distribution, minimizing neutral and phase-related issues during maintenance or fault events.
• 200 kAIC interrupting capacity gives you confidence handling substantial fault currents typical of industrial environments, while keeping the current pathway controlled and predictable.
• Seamless compatibility with the QMB fusible panelboard line keeps installations straightforward, avoiding compatibility headaches during upgrades or replacements.
• Robust specification set—400 A, 600 V, 3 poles, part number QMB365W, manufactured by Schneider Electric / Square D—engineered for reliability in commercial and light industrial applications.

Ideal use cases

• Feeder protection and load isolation in large commercial or light industrial panelboards, where dependable disconnection is critical for safety and reliability.
• Primary disconnects for three-phase electrical systems requiring rapid, reliable disconnection during maintenance or fault events.
• Upgrades or replacements within existing QMB panelboard configurations to maintain consistent protection standards without overhauling the distribution layout.

Practical notes for installation and operation

• Pair the QMB365W with the correct fuse class to achieve full load disconnect and overcurrent protection.
• Verify compatibility with your QMB fusible panelboard before installation to ensure optimal performance and safety margins.
• Follow applicable electrical codes during installation to maintain compliance and safe operation.
• Label and document protective devices clearly for maintenance and safety checks, making routine inspections faster and more accurate.

The QMB365W stands out by delivering balanced phase isolation and substantial fault-current handling in a compact, panelboard-friendly package. It’s the reliable choice for facilities that demand robust protection, easy maintenance, and seamless integration within Schneider Electric’s QMB system. Whether you’re upgrading aged gear, rewiring a new distribution point, or refreshing a panelboard lineup, this 3-pole fusible switch provides a clear, dependable path to safer, more efficient electrical distribution.